Apparatus for generating steam



Oct. 25,1932. wfD. LA MONT APPARATUS FOR GENERATING STEAM original Filed July 28 1927 IN V EN TOR.

ATTORNEYS cocoa 0 0 oooooooou ouaooooo WALTER D. LAMONT A/ 1Z2 rSpumL Patented Oct. 25, 1932 a "UNITED STATES PATENT: OFFICE WALTER DOUGLAS LA MONT, OF NORTH COLEBROOK, CONNECTICUT, ASSIGNOR TO LA MONT CORPORATION, OFNEW YORK, N. Y., A CORIORATION OF NEW YORK APPARATUS FOR GENERATING STEAM Original applicationfiled July 28, 1927,

This invention relates to a process of and an apparatus for generating steam, and particularly toa steam generator in which there is a positive and controlled supply of water '5 to the steam generating elements.

In United States reissue Letters Patent No. 16895, granted March 6, 1928, -is disclosed a steam generator in which the water tobe converted into steam is introduced into the upper end of a steam generating tube in quantity greater than can be converted into steam in its passage through the tube, but less than suflicientto tend to fill the cross section of the tube as it gravitates through the tube,

charged from the lower end of the tube and provision being made outside the tube for separating the steam and the water and continuously returning the separated water: to the upper end of the tube." In the construe tion disclosed in the said reissue Letters Patent, gravity is employed as the primary force to cause the fiow of water through the steam generating tube and to cause a film of water to be extended upon the inner surface of the tube, the outer surface being exposed to the steam generating heat. a g

Steam generators of the type'disclos'ed 1n the above-identified reissue Letters Patent in water tube boilers.

In the generator of the reissue Letters Pat-q ent above-identified, control of the input of water into the generating tube necessarily insures the provision of space for the free escape of the steam generated through the surface tension of the water since gravity maintains a continuous flow of the water through the tube and there is therefore no opportunity for the water, controlled in quantity at the input, to accumulate in'the tube and form steam locks or otherwise interfere with the free escape and free How of the generated steam. I have now discovered,

both the water and the steam-being dishave in use shown very high degrees of steam ameter or of the sizes now in general use Serial No. 209,024. Divided and this application flld 'April 15, 1931. Serial No. 530,227. 1

is made for establishing and maintaining a continuous unidirectional movement of steam and water through the tube toward a common discharge end and the water flow through the tube is adjusted to a rate greater than the rate .ofsteam generation but less than sufficient to cause interference with the steam flow by the water or with the separation ofthe steam from the water inside the tube. By my new discovery 1 have made it possible to employ the broad principles of steam generation of the said reissue Letters Patent in steam generators in which the tubes are either horizontal or are so inclined that a the intake ends of the tubes are lower than the discharge ends or are otherwise arranged sothat the flow of water therethrough is not materially aided by gravity.

. I have further discovered that by adjusting the rate of flow of the water through a steam generating tube in relation to the steam generating capacity of the tube, when the tube is so positioned tha water must flow through at least a part thereof without the aid of or against gravity, and, in this adjustment, taking into consideration the diameter of the tube, a condition may be obtained in which there will be a continuous unidirectional flow of both steam and water through the tube without appreciable interference with the steam flow by the water or with the water flow by the steam and in which, nevertheless, there will be such turbulence that the inner surface of the tube willbe constant-' ly protected throughout its extent by the Water, that is, t will be constantly wetted. In other words, even in tubes of comparatively small diameter, so arranged that'the flow of water therethrough is not materially aided by gravity, I have discovered that by proper adjustment of the amount of water continuously'supplied to the tubes in relation to the rate of steam generation and in relation to the tube diameter, rapid and continuous generation of steam may be effected without producing in the, tube such hydraulic pressure as would cause steanrlocking or would otherwise interfere with the freedom of flow of the steam, and that there will be a continuous and substantially uniform movementof steam and water through the tube'through-- out the entire operation thereof.

\ In its preferred embodiment, the invention will employ the closed circuit principle of said reissue Letters Patent, the excess water discharged from the generating tube being returned to the intake end thereof, but it will be apparent that in its broader aspects the invention has a still wider range of utility. In practice" there are many fields in which the invention, both in its preferred embodiment and in modifications thereof, may

find useful application such, for example, as

in the generation of steam for automotive vehicles such asrall cars, locomot1ves, automobiles, including trucks, airplanes, and in lower than the discharge ends.

many other places where-it is desirable to have the generating tubes arranged in either a horizontal position or with the intake ends It will be apparent also that the invention is particularly useful wherever either horizontaltubes or tubes with their-intake ends lower than their discharge ends are tobe employed and, for structural or other reasons, such as closer spacing of tubes or increase ofv heat-absorbing surface in a small space, it is'desirable that tubes of, comparatively small diameter be employed.

The invention and its applications will be bettermnderstdod by more detailed consideration of the embodiment illustrated by way of example in the accompanying drawing, which drawing, however, is more or less schematic but illustrates a practical way of applying the principlesof the invention without including many details which would, of

' course, be supplied in practice by the ,de-

' signer and engineer for the more convenient and automatic control of various functions.

' Referring to the drawing: 4

; Figure 1 is a side elevation showing more section of vehicle may be utilized to-supporta casing for the steam generating elements. This tea e979 casing is shown at 1 and extends from front to rear of the vehicle and preferably the under and upper portions are formed each of two plattes separated by an insulating space. In the embodiment illustrated, the plates are separated by partitions 2, Figure 5, running transversely of the frame and providing dead air spaces; These partitions are preferably separated from the casing plates by strips 3 of heat-insulating material. The casing 1 is closed at the front by a plate 4 but the rear is open and covered by a screen 5, through which the exhaust combustion gases flow. The usual hood is somewhat modified and consists of an inner, casing 6 and outer casing 7, as shown in Figures 1 and 3, thus providing a space therebetween through' which air may flow to b'e utilized in promoting combustion. As shown, the combustion chamber occupies the major portion of the hood space and thus provides a combustion chamber of ample size. A fan 8 suitably supported on the front portion of the outer casing 7 forces air into and around the space between the casings 6 and/Z. The combustion fuel is supplied through a nozzle shown conventionally at 9. Suitable means, not shown, is provided for burning the fuel within the casing or chamber 6, the flow of air eing around the walls of the casing 6 and between it-and the casing 7, suitable passages being provided so that the air enters alongside of the combustion nozzle 9. The hot gases then come in direct contact with the steam generating elements 10' and after passing lengthwise of the tubes are discharged through the screen 5 at the rear end of the vehicle.

IOU

The tubes lO constitute the steam generatll lg elements-which confine the water in heat exchanging relation with" the heating gases,

and they, are, suitably supported within the casing andbetween'the upper and. lower members thereof. These tubes are preferably of relatively small diameter, for example of an inch outside diameter and inch inside diameter, Several sets of tubes are shown arranged one above the other, and each set of tubes is supplied with water for steam generation by a distributing tube 11 carried by a header 12. This distributing tube is shown in enlarged detail in Figure 4 .and is semi-circular in form with small orifices, one registering with each generating vtube 10. For convenience of assemblage the headers 12 have holes boredtherethroughand one end of each tube is expanded into the header. The distributing tube 11 may beinserted into the header from one end thereof and-plugs 13 are inserted into the hole oppo- 7 site the tube end. In this way steam-tight joints are provided and flow of steam and water in one direction assured.

- In general for steam generators of the type described herein, it is desirable that the steam M. Langenerating tubes be relatively small, because they will stand higher steampressures with a thinner wall, than large tubes. They are therefore safer, lighter, and less expensive. They also permit close spacing, which is effective for high heat transfer by convection. On the other hand, where the tubes are ex posed to radiant heat and where the advantage of close spacing of the tubes does not enter so much as a factor, somewhat larger tubes may be utilized to provide a larger space for the larger amountrof steam generated. The increased amount of water required by such a tube subjected to the usually intense heat of radiation permits a larger orifice in the distributing tube, which is desirable in order to avoid the danger of clogging, and to insure the introduction into the tube of suflicient water in excess of the evaporating capacity thereof. The tube, however, must not be so large as to'interfere with the proper protection of its surface by the contact and flow of the water thereover.

Under some conditions, in a tube of too great diameter there is danger of hydraulic action, resulting in steam pockets with a large surface of the tube unwetted and corresponding danger of burning.

When convection gases are used, as small a tube as possible is desired in order that a great number of tubes closely spaced may occupy a given cross section, thus providing for concentration of the heating surface in the .cross section of the gas passage, thus increasing the rate of heat transfer. Another advantage in smallness of tube is that a large heating surface can be placed in the gas passage without necessitating the use of extremely long tubes. This is especially desirable where there is limitation of length of tube. A small tube under convection conditions may likewise be used because the evaporation usually is not so great as under radiant heat conditions and therefore thev amount of water necessary, to be introduced into the tubes is relatively smaller and even though the orifice in the tube is also smaller, because of the decreased flow thereis less danger of foreign material reaching the orifice and-causing clogging. It is apparent, however, that the limit of smallness is reached when the orifice in the distributing tube must be made so small that it is not practical to introduce through it the quantity of water necessary to provide an excess over that evaporated by the tube but limited and adjusted in relation to the rate of steam generation and in relation to the tube diameter as described above. Therefore, although the invent1on 1s not restricted to any exact size of tube, with due regard to the conditions 'outlined, it is preferred that the tubes be rela diameter. In other cases, however, tubes. of

larger diameter, for example to 1 or 1% outside diameter with suitable wall thickness have been successfully used. In

. certain cases even larger tubes properly prosectional area. These orifices thus serve to restrict the supply of water and so leave space for the steam within the generating tubes. The water to replace that evaporated in the tubes is obtained froma tank 14 connected by a stand pipe 15 to a water delivery pipe 16, from which run branch pipes 17 for supplying each intake or distributing header 12,

" of which four are shown in Figure 1. It is,

of course, to be understood that the number of tubes and headers will vary according to the power requirements and other conditions of the'particular vehicle upon which they are used. 1

The pump 19 is connected to draw water from the tank or pot 20 and to dischargeinto the pipe 18 connecting the pump to the delivery pipe16 and thereby to the headers 12. As shown in Figure 6, the pump 19 may be mechanically connected as by ashaft 40 to a driving motor 41 which may be a steam turbinc or other'power means. The turbine as shown in Figure 6' is supplied with steam through the pipe 42 controlled by the valve 43 and the steam exhausted from the turbine is discharged through the pipe 44. The pump 19 when driven by the turbine delivers the water through the pipe 18 against the head maintained in the tank 14, thereby supplying the necessary head of water to the d stributing tubes .11 in the headers 12. The size of the pump is so calculated and the speed at which it is driven by the turbine is so calculated and adju ted as by controlling the steam supplied to the turbine that water in proper quantity. as described above, is delivered into the tubes through the orifices in the distributing tubes 11. I I I Due in part to the force of the waterinjected into the tubes through these orifices and in part to the expansive and propelling force of the steam formed in the. generating tubes and in contact with the water. the steam carries or sweeps the water through the tubes toward the rear or discharge end thereof with suchforce and velocity and wlth such interaction due to the process of ebullition in view of the size of the tubes used, that the water is continuously brought into contact with inner surface of the tube.

the inner surface of the tubes which is thereby constantly wetted. The steam which is rapidly formed from the water in contact with the tube surface escapes freely into the space left within the tube, Whereafter its flow toward the discharge end of the tube is utilized to spread the water along and around the Steam and water are discharged into a pot where the Water is taken up by'the pump and returned to the intake manifold. The separated steam passes into a pipe 21 provided with a safety valve 21a and then to athrottle valve 22 controlled by means of a pivotally mounted handle 22a.

1 When the throttle valve is opened steampasses through a pipe 23 to the engine 24: suitably supported as by a bracket 25 depending from the vehicle frame and by the rear axle of the vehicle. Other forms of support may,

of course, be used. The exhaust steam fromv the engines flows along pipe 26 upwardly through a pipe 27 to a condenser 28. A pump 29 connected by a pipe 30 to the water delivery pipe 16 delivers the condensed steam thereto. I

lln order to equalize pressure in the pot 20 and supply tank 14, asmall pipe 31 con necting the two is provided, preferably with a restricted portion, as shown at 32, Figure 1.

When the piping arrangement as shown, when the pump 19 stops, the tubes 10 are filled with water from the tank 14. As soon, however, as the pump starts again the tank 14: begins to fill, due to the restricted orifices in the intake manifolds. When it is necessary to supply additional Water to the-system this may be conveniently done through the tank 14, which is provided with a cap 33 for thispurpose and pipes 15 and 31 are provided with valves 35 and 36 respectively to enable the tank 14 to be entirely shut ofi from the system when it is being filled. Normally both valves are open.

The operation will be apparent from what has been already stated but it may be briefly summarized as follows: The fuel to be burned entering through the nozzle 9 is supplied by the fan with air for its combustion and the combustion gases, after passing over the tubes 10 and heating them to the desired steam generating temperature, pass out at the opening 5.

The water supplied by the pump 19 to the intake manifolds in the several headers 12 enters the tubes 10 through the orifices and steam is rapidly generated from the water as it-passes along the tubes 10, the steam being finally separated in thepot 20 from the unevaporated Water which is returned again to the headers by the pump 19. The steam utilized in the engine is passed through the condenser and the condensed steam is also returned to the headers 12 as feed water,

sufficient pressure to maintain the desired head of water in the tank 14:, but even if this pressure should be a little greater than necessary, a small amount of water will be carried over to the pot20, but onlya small amount, due to the restriction 32 in the connection 31;

Although in the above described embodiment the flow of steam in the tubes is longi- V tudinally of the vehicle, it is nevertheless within the spirit of the invention to arrange the tubes so that the flow of steam therein is transversely of the vehicle or to arrange them in any suitable position in which gravity does not materially aid the water to flow therethrough. The flexibility of application of the invention to various types of apparatus to generators having the steam generating elements in various positions and arrangements and subjected to difierent kinds of heat and to different rates of heat transfer as indicated above rests on the utilization of the force of the flowing steam and the turbulence of ebullition to carry the water along the tube and to cause it to wet the inner surfaces thereof.

It will be apparent that with a tube subected to heat conditions which will produce a given amount of steam generation, three factors, as hereinabove suggested, must be taken into consideration in producing the preferred embodiment of the present invention: (a) the portion of the tube taken up by the steam flow should be so restricted as to main tam the velocity required to give force to the flow of the steam; (b) the tube should be of such internal cross section that the inner wall surfaces will be brought into such close relation that the water may be thrown thereagainst and swept thereover-in a layer of film in contact therewith due to the turbulent action of the steam and water flow; and (c) the amount of water delivered into the tube should be so adjusted as not to interfere with the steam flow while providing an excess over the amount that the tube can convert into steam in its passage therethrough. Elements or tubes operating under these conditions may be placed in any position without regard to the necessity for maintaining the flow of water therethrough by the action of gravprotected against burning out even under extremely high rates of evaporation.

This method of steam generation also makes it possible to set tubes in any. desired position in relation to the gas flow or the combustion chamber or to suit the form or space conditions of the generator or the furnace. For example, the steam generator will operate efliciently in an automobile or other vehicle which runs uphilland downhill or is otherwise at times out of normal position,

regardless of the direction of steam and water flow under these conditions. Similarly, tubes generating steam on the principle of the invention may be placed in horizontal positions adjacent the walls of a boiler furnace or inclined upward or partly in one di rection and partly in another or bent around a corner or to avoid a wall opening or to meet other conditions as required by convenience or the peculiarities of the design. Since the steam flow effects the flow of water through the tubes and spreads itover the surfaces thereof unaided by gravity and space is left in the tube for the generated steam, the surfaces are continually wetted and the steam is discharged freely from the tube together with the water in excess of that evaporated into steam. In addition to the ease of application to many fields of steam generation the invention makes possible the design of generators of compact construction and safe operation at low cost and for high capacity and efficiency as" well 'as great flexibility of operation.

This application is a division of my copen ding application for steam generator for automotive vehicles, Serial No. 209,024, filed July 28, 1927.

What is claimed is:

-1. The process of generating steam in a tube so positioned thatwate'rfiflowing therein toward the discharge end thereof must flow through at least a part thereof without the aid of or against gravity, which consists in applying steam generating heat to said tube, feeding water into said tube at such a rate with respect to the rate of applying the heat to the tube as to exceed the rate of steam generation of the tube but at a rate less than suflicient to fill said tube, said rate of feeding being so adjusted with respect to the volume of steam generated that said steam will by its passage through said tube cause said water to be spread around and along the interior surface ,of said tube.

generation of the tube but at a rate less than suflicient to fill said tube, said generated steam being so confined in its flow toward the discharge end of the tube. that in consideration of said rate of feeding the'steam will by its passage through said tube cause said water to be spread around and along the interior surface of saidtube.

3. The process of generating steam in a tube so positioned that water flowing therein toward the discharge end thereof must flow through at least a part thereof without the aid of or against gravity, which consists in applying steam generating heat to said spread the water and tokeep the tube wet throughout all parts of its length.

4. The process of generating steam inv a tube so positioned that water flowing therein toward the discharge end thereof must flow through at least a part thereof without the aid of or against gravity, which consists in applying steam generating heat to said tube, supplying water to the tube at a rate greater than the rate of steam generation in the tube but at a rate less than sufficient to tend to fill the tube or to interfere with the flow of steam through the tube at said rate of steam I generation, and withdrawing the excess water from said tubeat a rate to maintain the tube less than full of water and to insure the steam spreading the water over the surface of the .tube to maintain it wet.

, 5. The process of generating steam in a tube so positioned that water flowing therein toward the discharge end thereof must flow through at least a part thereof without the aid of or against gravity, which consists in applying steam generating heat to said tube, supplying water to the receiving end of the tube at a rate greater than the rate of steam generation in the tube but at a rate, less than suflicient to tend tofill the tube when generating steam at said rate, said rate of supplying the water being so related to the rate of steam generation that the volume of steam flowing in the tubetoward the discharge end causes the excess water to flow toward the discharge end, withdrawing the excess water discharged from said tube and returning it to the receiving end thereof. I

6. The process of generating steam in a tube so positioned that water flowing therein toward the discharge end thereof must flow of or against gravity, which consists in applying steam generatingheattosaidtube,supplying water to the receiving end of the tube at a rate greater than the rate of steam generation in the tube but at a rate less than sufficient to tend to fill the tube when generating steam at said rate, said rate of supplying the water being so related to the rate of steam generation that the volume of steam flowing in the tube toward the discharge end causes the excess water to flow toward the discharge end, a,

withdrawing the excess water discharged from said tube and returning it to the receiving end thereof together with sufficient additional water to maintain the aforementioned rate of input.

7. The process of generating steam in a confining element so positioned that water flowing therein toward the discharge end thereof must flow through at least a part thereof without the aid of or against gravity, which consists in applying steam generating heat to said element, continuously delivering water to said element at a rate which exceeds the rate of steam generation, restricting the rate of delivery of water to the element in relation to the rate of steam generation and in relation to the confinement of the steam and water within the elements, so that the water occupies a relatively small proportion of the internal cross-sectional area of said element, and causing the steam as it is generated to flow in said element in contact with the water to. effect a continuous flow of the water in the same direction as the steam flow while the water continues in said heat exchange relation.

8. The process of generating steam in a tube subjected to steam generating heat and having its intake end not higher than some other p art. fo f its length, which consists in continuously delivering water to said intake end of the tube-in quantity less than sufiicient to.

tend to fill the cross-sectional area thereof but greater than can be evaporated in its flow the'rethrough, maintaining such a cross-sectional area of the flow through the tube that the flow' of steam causes the water to flow through the tube and wet the surfaces thereof, and continuously removing the unvaporized water, discharged from said tube.

9. The process of generating steam in a tube so positioned that its receiving end is at substantially the same or at a lower level than the discharge end which consists in applying steam generating heat to said tube, continu-- ously supplying water to the receiving end of the tube, so restricting the input of water in relation to the volume of steam generated within the tube that the tube receives a quantity of water greater than its evaporating capacity but less than suflicient to occupy the full cross-sectional area of the tube in its said tube, delivering water into one end of the tube, limiting the water delivered into the tube to a quantity which is in excess of the steam generation within the tube, but such that the water does not interfere with the steam flowing through the tube in a continuous stream, causing the generated steam to flow toward the other end of the tube while preventing discharge thereof from the water receiving end of the tube, and causing the steam to act upon the water within the tube to spread the water over the inner surface of the tube and maintain it wet.

11, The method of insuring the wetting o the steam generating surfaces of a steam generating tube to one end of which water is deliv-ered and from the other end of which steam is discharged which tube is. so positioned that the flow of water therein, at least for a portion of its length, is not in the direction of the action of gravity, which consists enough space to interfere with said steam flow and to cause the steam intermittently to force the water from the discharge end of the tube and leave surfaces thereof dry.

12. The process of generating steam in a I closed circuit which includes a steam generating tube so positioned that the water flowing therein toward the discharge end thereof must flow through at least a part thereof without the aid of or against gravity, which consists in applying steam generating heat to said tube, causing the water to flow continuously into the intake end of said tube in quantity in excess of the steam generating capacity thereof, continuously withdrawing steam and water from the discharge end of said tube in such quantity in relation to each other and in relation to the quantity of water entering the intake end of the tube that the, steam 'flow's in a continuous stream in said tube and causes the continuous fiow of the water through said tube while maintaining the surfaces of the tube wet, and returning the water thus withdrawn from the discharge end of the tube to said intake end of the element.

' 13. The process of generating steam in a steam generating element having a water inlet-at oneend thereof and so positioned that water flowing therein toward the other end thereof must flow through at least a part I therein; preventin thereof without the aidof or against gravity which consists in applying steam generating heat to said element, delivering water into said element in excess of the steam generated ,9; the discharge of steam from said water inlet end of the element and causing it to flow toward the other end thereof in a continuous stream, confining the steam as it flows within the element so as to contact with the water, and so restricting the amount of water within the element that the flowing Steam effectively spreads the water.

overthe inner surface of the element Signed at New York, N. Y.', th's of April, 1931. v WALTER DOUGLAS LA MONT.

14th day 

